This invention relates generally to door locks and more particularly to door locks having a clutching mechanism for selectively connecting and disconnecting an external handle from a key spindle.
In response to the American with Disabilities Act and other state and local codes, levers have virtually replaced knobs in the marketplace. The benefit of added grip and leverage that levers provide to those with limited mobility has, however, created an opportunity for increased abuse or vandalism. This abuse often renders the lock inoperable and, in some cases, violates the security of the door, leaving computer and laboratory equipment susceptible to theft.
The foregoing illustrates limitations known to exist in present levered door locks. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
One prior art clutching door lock is described in U.S. Pat. No. 4,920,773, Surko et al. Surko discloses a clutching mechanism where a radially extending dog extends through a T-shaped slot in an outer spindle to connect a lever to the outer spindle. Another example of a clutching door lock is described in U.S. Pat. No. 2,998,274, Tornoe et al. Tornoe discloses a clutching mechanism having a center spindle that telescopes within the outside spindle and is selectively clutched to the outside spindle. A third example of a clutching door lock is described in U.S. Pat. No. 2,998,274, Russell. Russell discloses clutching an outside spindle to a telescoped center spindle by a clutch consisting of a finger and a notch comprising a longitudinal slot and an adjoining circumferential space. An example of a lock camming mechanism is described in International Patent Application WO 98/02630, published Jan. 22, 1998. U.S. Pat. No. 4,424,691 discloses: a door lock comprising: an inner handle; an outer handle; a chassis containing a latch retractor; an inner spindle having a latch scoop thereon, the latch scoop being operably connected to the latch retractor, the inner spindle being keyed to the inner handle; an outer spindle being keyed to the outer handle; a key spindle positioned within the outer spindle, the key spindle having a latch scoop thereon, the latch scoop being operably connected to the latch retractor, and having a cat therein and a key operated cylinder operably connected to the cam.